Abstract: Pressure drop type instability of supercritical endothermic hydrocarbon fuel supply system was founded in an experiment. In order to analyze the instability mechanism and the effects of fuel cracking characteristic on the stability of the fuel supply system, a zero-dimension homogeneous model was established. Instability simulation results of fuel with different cracking characteristic were compared. The results show that there exist two instable region in the supercritical hydrocarbon fuel supply system, namely, critical temperature region and cracking temperature region. Based on the excellent agreement between the experiment data and the simulation results calculated by the zero-dimension homogeneous model, the instable mechanism is interpreted. As a link in the positive feedback loop, the acute decrease of the fuel density is a main factor resulting in the instable phenomenon. Based on the compared simulation results, the more acute the density changes with temperature while the fuel is cracking, the more instable the system will be. 

Key words: Cooling system; Hydrocarbon fuel; Instability; Cracking

摘要： 通过实验研究发现了超临界吸热型碳氢燃料供油系统的压力降型不稳定现象。为了研究稳定机理和超临界吸热型碳氢燃料裂解特性对供油系统稳定性的影响,建立了零维平衡流模型,并针对不同裂解特性的燃料进行了对比仿真。研究结果表明,由于裂解反应的发生,超临界碳氢燃料供油系统存在临界区和裂解区两个不稳定区间。基于零维平衡流模型较好地复现不稳定实验现象,不稳定机理得到了详细的解释。密度随温度的变化是系统正反馈的重要环节之一,其剧烈的变化率是导致系统不稳定的主要原因,燃油裂解速率越快,其裂解产物密度相对变化率随温度变化越大,越容易引起供油系统的不稳定。 

关键词: 冷却系统;碳氢燃料;不稳定;裂解 